From Wikipedia, the free encyclopedia

Jump to: navigation, search
A "cantenna" is also a brand name for a dummy load.
A cantenna.

A cantenna is a directional waveguide antenna for long-range Wi-Fi used to increase the range of (or snoop on) a wireless network.


[edit] Origin of the name

The term 'Cantenna' originally referred to a product sold by Heathkit Co. in Benton Harbor, MI, USA. It was a 50-ohm resistive load used by radio amateurs.[1] However, in the more casual vernacular of the Do-It-Yourself community, it has functionally become a portmanteau of can (i.e. an empty Pringles can, see below) and antenna, since they're used to broadcast (and receive) signals, and not just terminate them.

Cantenna dummy load suitable up to 30 MHz and up to 1 kW

[edit] Construction

Although the original design was based on a Pringles potato chip can, a cantenna can be made from various cans/bottles. These include antennas on both the ground and antennas heightened by means of a pole. [2]

[edit] Example of a frequently used construction

A commonly used construction - which is quick, easy, and inexpensive due to use of readily obtained materials - is as follows:

  • Four small nuts/bolts;
  • A short length of medium-gauge wire;
  • A tin can roughly 8 cm (3.15 inches) in diameter, such as a Pringles canister. The longer the better; and
  • An N-Female chassis mount connector, available at many electronic supply stores.

[edit] Other constructions

A cantenna may be optimized by using a can with the right measurements. Effective sizes include:

  • 149.3 mm length for a 84 mm diameter can
  • 128.2 mm length for a 90 mm diameter can
  • 110 mm length for a 100 mm diameter can
  • 101 mm length for a 110 mm diameter can [3][4]

The addition of a pole or other method of elevation can also increase the range tremendously.

Other antenna-designs using WiFi dongles may also be created, for instance omnidirectional, sectoral, yagi-antennas, quad-antennas and biquad-antennas[5], and parabolic dishes or grids. At present, the most potent antenna for its size is a waveguide, but they have a relatively narrow signal path.

Several documents have been open-sourced to create these different types of antenna yourself, with one of the most popular[citation needed] (open-source) books now being the Wireless Hacks by Rob Flickenger [6] For extra references and pictures, the Instructables websites may also be used. [7]

[edit] Usage

While cantennas are useful for extending a wireless local area network (WLAN), the tiny design makes them ideal for mobile applications such as wardriving. The design of the cantenna is so simple that it is often the first antenna WiFi experimenters learn to build. Cantennas can even be used to increase cell phone range,[8] improving reception and decreasing noise.

[edit] See also

  • FON#La_Fontenna, a omnidirectional, cheap and high power antenna to distribute internet access around the world using a series of wireless LAN's
  • WokFi antenna
  • WarXing

[edit] External links

[edit] References

  1. ^ Hutchinson, Chuck. (May 1984). "Heathkit Cantenna, Model HN-31A". QST. p. 42.
  2. ^ Cantenna build on a pole (includes construction plans)
  3. ^ Optimal cantenna dimensions. Found to be dead on 2009-1-11.
  4. ^ Antenna Theory: Analysis and Design by Constantine A. Balanis
  5. ^ WLAN-Richtfunk mit Hausmitteln - Worauf es beim Selbstbau einer leistungsfähigen Richtantenne ankommt -Article describing the use use of Yagi, quad and biquad-antenna's with WiFi dongles)
  6. ^ Wireless Hacks book by Rob Flickenger (open-source version)
  7. ^ Instructables DIY Cantanna/antenna pictures
  8. ^ MAKE: Blog: Cell phone - Cantenna diagram and parts list
Personal tools